Reduce slope finder multiplier to 2 to prevent trigger jumps

This is necessary because fixing the correlation bug makes history
comparisons weaker relative to the slope finder. This would result in
waveforms with multiple edges per cycle jumping between rising edges
mid-note even at reasonable settings (edge strength = buffer strength).

corrscope/triggers.py

@@ -438,7 +438,7 @@ class CorrelationTrigger(MainTrigger):
         slope_width: float = np.clip(cfg.slope_width * period, 1.0, self.A / 3)
 
         # This is a fudge factor. Adjust it until it feels right.
-        slope_strength = cfg.edge_strength * 5
+        slope_strength = cfg.edge_strength * 2
         # slope_width is 1.0 or greater, so this doesn't divide by 0.
 
         slope_finder = np.empty(kernel_size, dtype=f32)  # type: np.ndarray[f32]